Bones can become damaged as a result of accident or illness. Such damage can be, for example, to the articular cartilage covering the ends of the bones at a joint as well as the intra-articular cartilage between the ends of the adjacent bones of the joint. When the damage to the joint is severe, a joint endoprosthesis can be implanted to improve the comfort and mobility of the patient.
Joint endoprostheses have been developed to replace native tissue of several human joints. There are a variety of knee prostheses, hip prostheses, shoulder prostheses, ankle prostheses and wrist prostheses available to relieve patient suffering. Such devices are made by and available from, for example, DePuy Products, Inc. and DePuy Orthopaedics, Inc. of Warsaw, Ind.
Standard joint endoprostheses include metal components that are affixed to the articulating ends of the bones of the joint and commonly include a bearing component positioned between the metal components. Standard bearing components of joint endoprostheses have a surface against which one of the metal components articulates. For example, hip endoprostheses include a metal femoral component to be affixed to the proximal femur and a metal cup to be affixed to the acetabulum. Many of these standard hip endoprostheses include a liner in the acetabular cup against which the femoral component articulates. Knee prostheses commonly include a femoral component to be affixed to the distal femur and a tibial component to be affixed to the proximal tibia. Bearings are typically between the femoral and tibial components. Similar systems with bearings are available to replace other joints in the body. Such endoprosthesis systems are commercially available from DePuy Orthopaedics, Inc. of Warsaw, Ind.
Orthopaedic prosthetics are also used to replace bone lost in the treatment of various bone cancers. These orthopaedic prosthetics may include elements of a joint endoprosthesis as well as components to replace intercalary bone loss. Such prosthetics are made by and available from DePuy Products, Inc. and DePuy Orthopaedics, Inc. of Warsaw, Ind.
Trauma products are also available for treating patients suffering traumatic injury, such as bone fractures. Trauma products frequently include orthopaedic components such as bone screws, bone nails, bone plates and fixators, for example. Such trauma products are commercially available from DePuy Trauma and Extremities of Warsaw, Ind.
Each of the foregoing types of devices typically requires a specialized set of instruments to ensure that the devices are properly implanted. Moreover, each of the different devices may require instruments of different sizes so as to ensure proper placement of the devices for different bone sizes. Accordingly, a large number of instruments are maintained in inventory, either at the care facility or under the control of a representative of the instrument manufacturer merely to support the implantation of the orthopaedic prosthetics.
Additionally, for a single surgery, such as a hip, knee, shoulder, and other joint replacement surgery (partial or total), six or more trays of instruments and trial implants may be required to be available for potential use. Prior to use in a subsequent procedure, each tray has to be re-sterilized even if the particular tray was not utilized during a prior procedure.
Therefore, a large number of instruments, some of which may be rarely used, must still be made available. The maintenance of a large inventory, while necessary, is not advantageous for many reasons. The instruments used in surgical procedures, for example, are typically fabricated from a metal such as stainless steel using traditional manufacturing processes such as machining, turning, and drilling. Although the foregoing materials and processes result in the production of effective instruments, the instruments are very heavy and expensive. Accordingly, the required instrument inventory is both extensive and expensive. Moreover, the instruments are heavy making movement of the instruments about a care facility cumbersome.
By way of example, patella drill guide instruments are regularly used in orthopaedic procedures. Typically, these instruments are produced by machining a stainless steel block. The areas that are subjected to the highest wear or load, however, are the actual guide holes. Thus, the bulk of the stainless steel merely adds to the weight and the expense of the device. Additionally, spikes are typically desired to be provided in order to facilitate stability of the guide during use. Because patella drill guide instruments are made of stainless steel, the addition of spikes requires welding the spikes onto the stainless steel block and then polishing and finishing the weld. Thus, the manufacturing steps and associated costs of the patella guide instruments are increased.
As a further example, known femoral distal cutting block instruments require a number of precision machining operations to produce the base block and pawl. Likewise, finishing guides require machining operations to form the various plates as well as turning operations to manufacture screws needed for assembly of the finishing guide.
The problems associated with the need to maintain a large inventory of heavy instruments is further compounded by the fact that some instruments are needed merely to manipulate other instruments. One such instrument is a tibial tray trial. The tibial tray trial includes a tray instrument which is machined in several steps as well as a handle instrument. The handle instrument is designed to be attached to the tray instrument and then to be removed once the tray instrument is in the desired position. Thus, additional instruments are required. Additionally, the release mechanism used, in addition to being heavy, includes a number of additional components, thereby increasing the complexity of the instrumentation.
In addition to the foregoing limitations, any delay due to the shipping and re-sterilization of the instruments adds to the cost of providing the instruments. Also, as implant systems or instruments are modified or replaced, the inventory of such systems or instruments must also be replaced.
Therefore, a need exists for an orthopaedic instrument which is lighter than an all-metal instrument but which provides wearability comparable to the all-metal instrument. A further need exists for an instrument which is inexpensive and which is easy to manufacture. A further need exists for new complex instrumentation to be rapidly and inexpensively produced.